assertTrue(queryFieldConfig.apiResponseFieldSet.contains("api2"));
        assertTrue(queryFieldConfig.apiResponseFieldSet.contains("api3"));
    }

    @Test
    public void test_highlightedFields_withNull() {
        queryFieldConfig.highlightedFields = null;

        // When highlightedFields is null, the method should handle it gracefully
        // or throw an exception. Test the actual behavior.